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Morrow lithofacies and pore types: Sorrento field (view source)
Revision as of 21:56, 31 January 2014
, 21:56, 31 January 2014Initial import
{{publication
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Predicting the occurrence of oil and gas traps
| chapter = Predicting reservoir system quality and performance
| frompg = 9-1
| topg = 9-156
| author = Dan J. Hartmann, Edward A. Beaumont
| link = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
By studying core and log data from one well (well 11, see Figure 9-86), we see a picture of a clastic reservoir with wide heterogeneity in total porosities, pore-throat sizes, and [[capillary pressure]]s. In addition, the depositional environment of these sandstones (fluvial valley fill and sandstone) indicates they probably have limited lateral continuity within the valley-fill complex.
==Reservoir lithologic description==
Morrow sandstones in the Sorrento field are slightly shaly, range in grain size from very coarse to fine, and are poorly sorted. As a consequence, pores and pore throats also have wide ranges in size. Hand-sample petrography indicates the dominant [[porosity]] is inter-granular micro- to megaporosity. Clay crystals create minor intercrystalline microporosity in larger pores. Moldic (cement solution?) porosity also may be present but is minor.
==Reservoir porosity and permeability==
Morrow sandstones in Sorrento field have a wide range in porosity and [[permeability]]. Maximum observed porosity (Φ) is 20-22%, but more typical values are 10-15%. Air permeabilities (K<sub>a</sub>) are as great as 1-2 darcies but more commonly are 200-500 md.
Below is a K<sub>a</sub>/Φ crossplot for well 11 (see Figure 9-87). Dots and polygons represent measured K<sub>a</sub>/Φ values. Curves are the graphical solution of Winland's r<sub>35</sub> equation<ref name=ch09r46>Pittman, E., D., 1992, Relationship of porosity to permeability to various parameters derived from mercury injection–capillary pressure curves for sandstone: AAPG Bulletin, vol. 76, no. 2, p. 191–198.</ref> and represent equal r<sub>35</sub> values (port size).
The crossplot shows a large variation in port size for the samples from well 11. Areas between dashed lines group points into beds with similar port size, or flow units.
[[file:predicting-reservoir-system-quality-and-performance_fig9-87.png|thumb|{{figure number|9-87}}. Copyright: Hartmann and ;<ref name=ch09r11>Coalson, E., B., Hartmann, D., J., Thomas, J., B., 1990, Applied Petrophysics in Exploration and Exploitation: Notes from short course sponsored by Univ. of Colo.–Denver, var. pages.</ref> courtesy RMAG.]]
==Extrapolated capillary pressure curves and pore types==
No capillary pressure measurements were available for this study. They were estimated-by plotting r<sub>35</sub> values on a semilog crossplot of fluid saturation vs. capillary pressure. A capillary pressure curve for each sample passes through its correlative r<sub>35</sub> value. Calculations of r<sub>35</sub> for well 11 indicate a large variety of capillary pressures and pore types. Pore types for the Morrow samples from this well are mega, macro, and micro.
The numbers on the curves in the figure below correspond to the numbers on the K<sub>a</sub>/Φ crossplot on Figure 9-86. Minimum water saturations (“immobile” water) estimated from log calculations let us extrapolate the P<sub>c</sub> curves into low S<sub>w</sub> ranges.
[[file:predicting-reservoir-system-quality-and-performance_fig9-88.png|thumb|{{figure number|9-88}}. Copyright: Hartmann and Coalson, 1990; courtesy RMAG.]]
==See also==
* [[Evaluation of saturation profiles]]
* [[Setting and structure of the Sorrento field]]
* [[Sorrento water saturation calculations]]
* [[Petrophysical analysis of Sorrento field wells]]
* [[Water saturation profile for Sorrento field]]
==References==
{{reflist}}
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Predicting the occurrence of oil and gas traps]]
[[Category:Predicting reservoir system quality and performance]]
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Predicting the occurrence of oil and gas traps
| chapter = Predicting reservoir system quality and performance
| frompg = 9-1
| topg = 9-156
| author = Dan J. Hartmann, Edward A. Beaumont
| link = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
By studying core and log data from one well (well 11, see Figure 9-86), we see a picture of a clastic reservoir with wide heterogeneity in total porosities, pore-throat sizes, and [[capillary pressure]]s. In addition, the depositional environment of these sandstones (fluvial valley fill and sandstone) indicates they probably have limited lateral continuity within the valley-fill complex.
==Reservoir lithologic description==
Morrow sandstones in the Sorrento field are slightly shaly, range in grain size from very coarse to fine, and are poorly sorted. As a consequence, pores and pore throats also have wide ranges in size. Hand-sample petrography indicates the dominant [[porosity]] is inter-granular micro- to megaporosity. Clay crystals create minor intercrystalline microporosity in larger pores. Moldic (cement solution?) porosity also may be present but is minor.
==Reservoir porosity and permeability==
Morrow sandstones in Sorrento field have a wide range in porosity and [[permeability]]. Maximum observed porosity (Φ) is 20-22%, but more typical values are 10-15%. Air permeabilities (K<sub>a</sub>) are as great as 1-2 darcies but more commonly are 200-500 md.
Below is a K<sub>a</sub>/Φ crossplot for well 11 (see Figure 9-87). Dots and polygons represent measured K<sub>a</sub>/Φ values. Curves are the graphical solution of Winland's r<sub>35</sub> equation<ref name=ch09r46>Pittman, E., D., 1992, Relationship of porosity to permeability to various parameters derived from mercury injection–capillary pressure curves for sandstone: AAPG Bulletin, vol. 76, no. 2, p. 191–198.</ref> and represent equal r<sub>35</sub> values (port size).
The crossplot shows a large variation in port size for the samples from well 11. Areas between dashed lines group points into beds with similar port size, or flow units.
[[file:predicting-reservoir-system-quality-and-performance_fig9-87.png|thumb|{{figure number|9-87}}. Copyright: Hartmann and ;<ref name=ch09r11>Coalson, E., B., Hartmann, D., J., Thomas, J., B., 1990, Applied Petrophysics in Exploration and Exploitation: Notes from short course sponsored by Univ. of Colo.–Denver, var. pages.</ref> courtesy RMAG.]]
==Extrapolated capillary pressure curves and pore types==
No capillary pressure measurements were available for this study. They were estimated-by plotting r<sub>35</sub> values on a semilog crossplot of fluid saturation vs. capillary pressure. A capillary pressure curve for each sample passes through its correlative r<sub>35</sub> value. Calculations of r<sub>35</sub> for well 11 indicate a large variety of capillary pressures and pore types. Pore types for the Morrow samples from this well are mega, macro, and micro.
The numbers on the curves in the figure below correspond to the numbers on the K<sub>a</sub>/Φ crossplot on Figure 9-86. Minimum water saturations (“immobile” water) estimated from log calculations let us extrapolate the P<sub>c</sub> curves into low S<sub>w</sub> ranges.
[[file:predicting-reservoir-system-quality-and-performance_fig9-88.png|thumb|{{figure number|9-88}}. Copyright: Hartmann and Coalson, 1990; courtesy RMAG.]]
==See also==
* [[Evaluation of saturation profiles]]
* [[Setting and structure of the Sorrento field]]
* [[Sorrento water saturation calculations]]
* [[Petrophysical analysis of Sorrento field wells]]
* [[Water saturation profile for Sorrento field]]
==References==
{{reflist}}
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Predicting the occurrence of oil and gas traps]]
[[Category:Predicting reservoir system quality and performance]]